Field of the Invention
The present invention relates to inspection apparatuses for inspecting targets using a plurality of lights, which have different polarization states from each other.
Priority is claimed on Japanese Patent Application No. 2014-113950, filed on Jun. 2, 2014, the contents of which are incorporated herein by reference.
Description of Related Art
Inspection apparatuses using polarized lights are for irradiating an inspection target with a light, which has a specific polarization state (a linear polarization state or a circular polarization state), receiving a plurality of reflected lights (or, a plurality of transmitted rights), which are obtained from the inspection target and have different polarization states from each other, and inspecting the target. Such inspection apparatuses are used for inspecting surface defects of products or internal defects of products (dust, scratch, non-uniformity, and the like).
Research and development of various devices using organic materials has been actively performed in light of the diversity of function and configuration of the organic materials. The inspection apparatuses are often used for inspecting the quality of thin films (organic thin films) using such organic materials. For example, the inspection apparatuses are often used for inspecting polarizing films, which are used for organic thin-film photovoltaic cells, organic Electro Luminescence (EL) displays, liquid crystal displays, and the like, Radio Frequency IDentification (RFID) tags using organic semiconductors, and the like.
Japanese Unexamined Patent Application, First Publication No. H09-178666 (hereinafter, referred to as “PTL1”) and Japanese Unexamined Patent Application, First Publication No. 2007-322316 (hereinafter, referred to as “PTL2”) disclose examples of inspection apparatuses using polarized lights in the related art. In particular, the PTL1 discloses an inspection apparatus using polarized lights that splits a reflected light from a surface of a steel plate, which is an inspection target, into three different types of polarized lights using a beam splitter, measures the polarized lights using a linear array camera, calculates the ellipse-parameters of the reflected light, and judges the type and grade of the surface defects of the inspection target. The PTL2 discloses an inspection apparatus using polarized lights that selects a plurality of liner polarized lights, which is the most suitable for the inspection, and irradiates an inspection target with the liner polarized lights, so as to overcome the situation where the change of the reflection plane caused by the movement of the inspection target makes the detection of defects difficult.
It is often the case that the above-stated thin film such as an organic thin film is manufactured by a continuous manufacturing process referred to as a “roll-to-toll process”. The above-stated continuous manufacturing process referred to as the “roll-to-toll process” continuously applies an organic material and the like while drawing a rolled film to form an organic thin film, then, rolls the film again, on which the organic thin film is formed. The inspection of the organic thin film manufactured by such a process is generally performed while the organic thin film to be inspected is being moved.
It seems that the inspection apparatus disclosed in the PTL 1 or the PTL 2 allows the inspection of the target while the inspection target is being moved. The inspection apparatus disclosed in the PTL 1 is suitable for inspection of surface defects of an inspection target, which has high surface reflectance, such as a steel plate, but the inspection apparatus is not suitable for inspection of the quality of, for example, an organic thin film (inspection whether an orientation of a molecular material is appropriate). This holds true for the PTL 2.